class A 
{
public:
	int _a;
};
// class B : public A
class B : virtual public A {
public:
	int _b;
};
// class C : public A
class C : virtual public A {
public:
	int _c;
};
class D : public B, public C {
public:
	int _d;
};
int main()
{
	D d;
	d.B::_a = 1;
	d.C::_a = 2;
	d._b = 3;
	d._c = 4;
	d._d = 5;
	return 0;
}
